CPT1: Stroke Flashcards
What percentage of:
- Does the brain weigh?
- CO does the brain receive
- O2 does the brain receive
- Glucose does the brain receieve?
- 2-3%
- 15%
- 20%
- 25%
What is a stroke?
“clinical syndrome consisting of ‘rapidly developing clinical signs of focal (at times global) disturbance of cerebral function, lasting more than 24 h or leading to death with no apparent cause other than that of vascular origin”.
Blood supply to part of the brain cut off
What types of strokes are there?
- ischaemic stroke (IS)
- Haemorrhagic stroke (HS)
- Transient ischaemic stroke - small cerebral arterial emboli that transiently blocks the vessel. Sympyoms and signs resolve within 24hr
What are symptoms of a stroke?
- Numbness, weakness or paralysis on one side of the body
- Severe headache
- Loss or blurred vision
- Slurred speach or trouble finding words or understanding speach
- Confusion or unsteadiness
If symptoms are required what is the acronum followed and what is important?
Symptoms need immediate action!!
F.A.S.T
- Face, Arms, Speech, Time
What alogrithm is followed to identify high risk patients of a stroke following a TIS
ABCD2
- A -Age (>=60 years, 1 point)
- B -Blood pressure at presentation (>=140/90 mmHg, 1 point)
- C - Clinical features (unilateral weakness, 2 points; speech disturbance without weakness, 1 point)
- D - Duration of symptoms (>= 60 minutes, 2 points; 10-59 minutes, 1 point)
- D - Diabetes? 1 point
Score ranges from 0 (low risk) to 7 (high risk)
Unilateral means weakness/ paralysis at one complete side of the body
What are modifiable risk factors which reduce chance of stroke?
-
Hypertension
- Hypertension = %25 get CVA
- Nomotension = 10% get CVA
-
Smoking
- 30-40% reduction in stroke risk if stop smoking
-
Salt and Blood pressure
- Reduce salt intake by 3g = BP reduced by 5 mmHg = ~25% fewer strokes
Hypertension stats
Hypertension
Hypertension 25 % get CVA
Normotensive 10 % get CVA
Relative risk 25/10 = 2.5
- a 5 mm Hg ê in BP - 10% ê stroke
- 10 / 5 mm Hg systolic/dias ê stroke incidence 38%
- Salt ê 3 g /day – 20-25% ê in stroke
- Diastolic 105 vs 76 mm Hg è x10 risk CVA
- 50% have previous sys BP > 140 mm Hg
• ê diastolic by 5 mm Hg mild/mod hypertension
ê stroke incidence 42% & fatal CVA by 45%
• Rx BP > 60 yr. ê CVA by 25-47%
v Systolic hypertension - >160 mm Hg.
– ê ISH by 11- 23 mm Hg. êCVA 36-42%
(13.7 to 7.9 events per 1,000 patient years)
– No evidence êBP post stroke êCVA
– ê BP within 3 days post stroke poor outcome
– ISH occurs in at least 15% of the over 60’s
Treating 1,000 pts for 5 years with ISH may prevent 29 CVAs
ISH = Isolated Systolic Hypertension
CVA = Cerebrovascular Accident
Smoking stast
Smoking.
Stop smoking reduces stroke risk by 30-40%
w Relative/rate ratio risk CVA é 1.5-2.0
w 12% of CVAs avoided if cigs never existed
w Middle aged men risk 4.1,ex smoker 1.9
w Over 20 cig/day higher risk
w Ex smoker risk decreased by year 5
Salt and BP stats
Salt and blood pressure.
ê salt intake by 3g (50 mmol) ê BP by 5 mm Hg. è ~25% fewer strokes & 40,000 fewer stroke deaths in UK/yr.
w ê NaCl by 5 g/day (83 mmol) ê BP by 7/3 mmHg
w Only need 10 mmol salt/day (0.6g)
w Take in about 160 mmol of salt/day
w What is normotensive in the elderly ?
w Benefit extends to younger, maximum in older
15% strokes proceed TIA
Aspririn may prevent 4% of strokes
What is the treatment for iscahemic stroke/ TIA?
- Fibrinolytics act as thrombolytics, activating plasminogen to plasmin. Decreased Fibrin leads to break down of thrombi
- Acute Ischaemic stroke NICE recommends Alteplase. BUT only under specialist supervision (neurologist). Increased risk of cerebral bleeding
- All recommendations (irrespective of ABCD2 score) recommend asprin (300mg/daily). Followed by specialist assessment (time and score dependent).
- Currently NICE has no recommendations to duration (aspirin). But in stroke, 300mg daily discontinued after 2 weeks. Subsequent long term anti-thrombitic therapy started (low dose asprin and dipyridamole combination; Asasantin)
What if the patient is intolerant or hypersensitive to aspirin?
•If aspirin not advisable due to hypersensitivity or intolerance even when aspirin and proton pump inhibitor used then use of clopidogrel monotherapy recommended.
Treatment of ISH and HS
Ischaemic stroke:
- Cause is usually hypertension. Acute treatment is thrombolytic (Alteplase) but only if used 4.5 hrs after 1st symptoms occur, after this, risk of intracerebral haemorrhage outways benefits.
Haemorrhagic stroke:
- Common cause of major disability/death is cerbral vasospasm. Occurs in ~25% of patients, usually 3 days after initial bleed.
- Nimodopine: Ca2+ channel blocker (dihydropyridine Ca2+ blocker). Affects smooth muscle in cerebral artery. Also may reduce excitotoxicity in ischaemic neurons.
- Use is restricted to spasm following subarachnoid haemorrhage.
What is the opinion on the use of statins?
Currently NICE do not recommend initiating treatment using statins in acute stroke.
BUT if patient already on statin, treatment should continue.
